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Wed, 4 Sep 2024 03:09:43 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org, david@redhat.com, willy@infradead.org, kirill.shutemov@linux.intel.com Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, mark.rutland@arm.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, jglisse@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dev Jain Subject: [PATCH v2 1/2] mm: Abstract THP allocation Date: Wed, 4 Sep 2024 15:39:22 +0530 Message-Id: <20240904100923.290042-2-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240904100923.290042-1-dev.jain@arm.com> References: <20240904100923.290042-1-dev.jain@arm.com> MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: CF084100006 X-Stat-Signature: xsfszba3m33fhp8agcw43putm6fzc88b X-HE-Tag: 1725444592-332899 X-HE-Meta: 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 AbtAIYaj QI8LqzKkvi2sMRM4HgJY3jp9WyPnu+oesRUGcFrOjR8rDs4nqTXw/UNpmOOwSSdZ70kSRgqMi0mOdWBqa++430DkBvjuIZx03G1vLePmSrNMIx6ugN4XoJe9mRvFeENoyNrdZuucMozqTbpXLxRaU2jlYug== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In preparation for the second patch, abstract away the THP allocation logic present in the create_huge_pmd() path, which corresponds to the faulting case when no page is present. There should be no functional change as a result of applying this patch. Signed-off-by: Dev Jain --- mm/huge_memory.c | 110 +++++++++++++++++++++++++++++------------------ 1 file changed, 67 insertions(+), 43 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 67c86a5d64a6..58125fbcc532 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -943,47 +943,89 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, } EXPORT_SYMBOL_GPL(thp_get_unmapped_area); -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, - struct page *page, gfp_t gfp) +static vm_fault_t thp_fault_alloc(gfp_t gfp, int order, struct vm_area_struct *vma, + unsigned long haddr, struct folio **foliop, + unsigned long addr) { - struct vm_area_struct *vma = vmf->vma; - struct folio *folio = page_folio(page); - pgtable_t pgtable; - unsigned long haddr = vmf->address & HPAGE_PMD_MASK; - vm_fault_t ret = 0; + struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true); - VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); + *foliop = folio; + if (unlikely(!folio)) { + count_vm_event(THP_FAULT_FALLBACK); + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK); + return VM_FAULT_FALLBACK; + } + VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) { folio_put(folio); count_vm_event(THP_FAULT_FALLBACK); count_vm_event(THP_FAULT_FALLBACK_CHARGE); - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK); - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE); + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK); + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE); return VM_FAULT_FALLBACK; } folio_throttle_swaprate(folio, gfp); - pgtable = pte_alloc_one(vma->vm_mm); - if (unlikely(!pgtable)) { - ret = VM_FAULT_OOM; - goto release; - } - - folio_zero_user(folio, vmf->address); + folio_zero_user(folio, addr); /* * The memory barrier inside __folio_mark_uptodate makes sure that * folio_zero_user writes become visible before the set_pmd_at() * write. */ __folio_mark_uptodate(folio); + return 0; +} + +static void __thp_fault_success_stats(struct vm_area_struct *vma, int order) +{ + count_vm_event(THP_FAULT_ALLOC); + count_mthp_stat(order, MTHP_STAT_ANON_FAULT_ALLOC); + count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); +} + +static void map_pmd_thp(struct folio *folio, struct vm_fault *vmf, + struct vm_area_struct *vma, unsigned long haddr, + pgtable_t pgtable) +{ + pmd_t entry; + + entry = mk_huge_pmd(&folio->page, vma->vm_page_prot); + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); + folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE); + folio_add_lru_vma(folio, vma); + pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); + set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); + update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); + add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); + mm_inc_nr_ptes(vma->vm_mm); +} + +static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf) +{ + struct vm_area_struct *vma = vmf->vma; + struct folio *folio = NULL; + pgtable_t pgtable; + unsigned long haddr = vmf->address & HPAGE_PMD_MASK; + vm_fault_t ret = 0; + gfp_t gfp = vma_thp_gfp_mask(vma); + + pgtable = pte_alloc_one(vma->vm_mm); + if (unlikely(!pgtable)) { + ret = VM_FAULT_OOM; + goto release; + } + + ret = thp_fault_alloc(gfp, HPAGE_PMD_ORDER, vma, haddr, &folio, + vmf->address); + if (ret) + goto release; vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); + if (unlikely(!pmd_none(*vmf->pmd))) { goto unlock_release; } else { - pmd_t entry; - ret = check_stable_address_space(vma->vm_mm); if (ret) goto unlock_release; @@ -997,20 +1039,9 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, VM_BUG_ON(ret & VM_FAULT_FALLBACK); return ret; } - - entry = mk_huge_pmd(page, vma->vm_page_prot); - entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); - folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE); - folio_add_lru_vma(folio, vma); - pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); - set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); - update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); - add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); - mm_inc_nr_ptes(vma->vm_mm); + map_pmd_thp(folio, vmf, vma, haddr, pgtable); spin_unlock(vmf->ptl); - count_vm_event(THP_FAULT_ALLOC); - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC); - count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); + __thp_fault_success_stats(vma, HPAGE_PMD_ORDER); } return 0; @@ -1019,7 +1050,8 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, release: if (pgtable) pte_free(vma->vm_mm, pgtable); - folio_put(folio); + if (folio) + folio_put(folio); return ret; } @@ -1077,8 +1109,6 @@ static void set_huge_zero_folio(pgtable_t pgtable, struct mm_struct *mm, vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; - gfp_t gfp; - struct folio *folio; unsigned long haddr = vmf->address & HPAGE_PMD_MASK; vm_fault_t ret; @@ -1129,14 +1159,8 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) } return ret; } - gfp = vma_thp_gfp_mask(vma); - folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, vma, haddr, true); - if (unlikely(!folio)) { - count_vm_event(THP_FAULT_FALLBACK); - count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK); - return VM_FAULT_FALLBACK; - } - return __do_huge_pmd_anonymous_page(vmf, &folio->page, gfp); + + return __do_huge_pmd_anonymous_page(vmf); } static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, From patchwork Wed Sep 4 10:09:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dev Jain X-Patchwork-Id: 13790324 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEC19CD3431 for ; Wed, 4 Sep 2024 10:10:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 449286B02D2; Wed, 4 Sep 2024 06:10:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3F9966B02D3; 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Wed, 4 Sep 2024 03:10:27 -0700 (PDT) Received: from e116581.blr.arm.com (e116581.arm.com [10.162.43.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9251E3F66E; Wed, 4 Sep 2024 03:09:52 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org, david@redhat.com, willy@infradead.org, kirill.shutemov@linux.intel.com Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, mark.rutland@arm.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, jglisse@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dev Jain Subject: [PATCH v2 2/2] mm: Allocate THP on hugezeropage wp-fault Date: Wed, 4 Sep 2024 15:39:23 +0530 Message-Id: <20240904100923.290042-3-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240904100923.290042-1-dev.jain@arm.com> References: <20240904100923.290042-1-dev.jain@arm.com> MIME-Version: 1.0 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 041AA180016 X-Stat-Signature: mzxxcmo3r5mcutcortwcurhq3hhruwao X-Rspam-User: X-HE-Tag: 1725444601-569112 X-HE-Meta: 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 2OLiGt5I 3GJ2u2pSfGKUxAMrYTqbyQY7RGZLwDJtEs+mAqI+RX+ZErt0Pp2v/0NsuhSexhlgRIYaW6MGMA6aGYGWLcKPUtnXy5ppr3DVC1bjuK6PcOkm4eO+d1cZd23BSrFs8kZvllwe4eE3xJuUtRaNTcECIo4uvSA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Introduce do_huge_zero_wp_pmd() to handle wp-fault on a hugezeropage and replace it with a PMD-mapped THP. Change the helpers introduced in the previous patch to flush TLB entry corresponding to the hugezeropage, and preserve PMD uffd-wp marker. In case of failure, fallback to splitting the PMD. Signed-off-by: Dev Jain --- include/linux/huge_mm.h | 6 ++++ mm/huge_memory.c | 79 +++++++++++++++++++++++++++++++++++------ mm/memory.c | 5 +-- 3 files changed, 78 insertions(+), 12 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index e25d9ebfdf89..fdd2cf473a3c 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -9,6 +9,12 @@ #include vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf); +vm_fault_t thp_fault_alloc(gfp_t gfp, int order, struct vm_area_struct *vma, + unsigned long haddr, struct folio **foliop, + unsigned long addr); +void map_pmd_thp(struct folio *folio, struct vm_fault *vmf, + struct vm_area_struct *vma, unsigned long haddr, + pgtable_t pgtable); int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 58125fbcc532..150163ad77d3 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -943,9 +943,9 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, } EXPORT_SYMBOL_GPL(thp_get_unmapped_area); -static vm_fault_t thp_fault_alloc(gfp_t gfp, int order, struct vm_area_struct *vma, - unsigned long haddr, struct folio **foliop, - unsigned long addr) +vm_fault_t thp_fault_alloc(gfp_t gfp, int order, struct vm_area_struct *vma, + unsigned long haddr, struct folio **foliop, + unsigned long addr) { struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true); @@ -984,21 +984,29 @@ static void __thp_fault_success_stats(struct vm_area_struct *vma, int order) count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); } -static void map_pmd_thp(struct folio *folio, struct vm_fault *vmf, - struct vm_area_struct *vma, unsigned long haddr, - pgtable_t pgtable) +void map_pmd_thp(struct folio *folio, struct vm_fault *vmf, + struct vm_area_struct *vma, unsigned long haddr, + pgtable_t pgtable) { - pmd_t entry; + pmd_t entry, old_pmd; + bool is_pmd_none = pmd_none(*vmf->pmd); entry = mk_huge_pmd(&folio->page, vma->vm_page_prot); entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); - pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); + if (!is_pmd_none) { + old_pmd = pmdp_huge_clear_flush(vma, haddr, vmf->pmd); + if (pmd_uffd_wp(old_pmd)) + entry = pmd_mkuffd_wp(entry); + } + if (pgtable) + pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); - mm_inc_nr_ptes(vma->vm_mm); + if (is_pmd_none) + mm_inc_nr_ptes(vma->vm_mm); } static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf) @@ -1576,6 +1584,50 @@ void huge_pmd_set_accessed(struct vm_fault *vmf) spin_unlock(vmf->ptl); } +static vm_fault_t do_huge_zero_wp_pmd_locked(struct vm_fault *vmf, + unsigned long haddr, + struct folio *folio) +{ + struct vm_area_struct *vma = vmf->vma; + vm_fault_t ret = 0; + + ret = check_stable_address_space(vma->vm_mm); + if (ret) + goto out; + map_pmd_thp(folio, vmf, vma, haddr, NULL); +out: + return ret; +} + +static vm_fault_t do_huge_zero_wp_pmd(struct vm_fault *vmf, unsigned long haddr) +{ + struct vm_area_struct *vma = vmf->vma; + gfp_t gfp = vma_thp_gfp_mask(vma); + struct mmu_notifier_range range; + struct folio *folio = NULL; + vm_fault_t ret = 0; + + ret = thp_fault_alloc(gfp, HPAGE_PMD_ORDER, vma, haddr, &folio, + vmf->address); + if (ret) + goto out; + + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, haddr, + haddr + HPAGE_PMD_SIZE); + mmu_notifier_invalidate_range_start(&range); + vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); + if (unlikely(!pmd_same(pmdp_get(vmf->pmd), vmf->orig_pmd))) + goto unlock; + ret = do_huge_zero_wp_pmd_locked(vmf, haddr, folio); + if (!ret) + __thp_fault_success_stats(vma, HPAGE_PMD_ORDER); +unlock: + spin_unlock(vmf->ptl); + mmu_notifier_invalidate_range_end(&range); +out: + return ret; +} + vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) { const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; @@ -1588,8 +1640,15 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); VM_BUG_ON_VMA(!vma->anon_vma, vma); - if (is_huge_zero_pmd(orig_pmd)) + if (is_huge_zero_pmd(orig_pmd)) { + vm_fault_t ret = do_huge_zero_wp_pmd(vmf, haddr); + + if (!(ret & VM_FAULT_FALLBACK)) + return ret; + + /* Fallback to splitting PMD if THP cannot be allocated */ goto fallback; + } spin_lock(vmf->ptl); diff --git a/mm/memory.c b/mm/memory.c index 3c01d68065be..c081a25f5173 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5409,9 +5409,10 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) if (vma_is_anonymous(vma)) { if (likely(!unshare) && userfaultfd_huge_pmd_wp(vma, vmf->orig_pmd)) { - if (userfaultfd_wp_async(vmf->vma)) + if (!userfaultfd_wp_async(vmf->vma)) + return handle_userfault(vmf, VM_UFFD_WP); + if (!is_huge_zero_pmd(vmf->orig_pmd)) goto split; - return handle_userfault(vmf, VM_UFFD_WP); } return do_huge_pmd_wp_page(vmf); }